Hydrocarbon hydroconversion process using sieve in alumina-silica-magnesia matrix

ABSTRACT

A hydrocarbon hydroconversion process comprising contacting a hydrocarbon feedstock and hydrogen with a catalyst comprising an alumina-silica-magnesia matrix containing a hydrogenation component, and a crystalline zeolitic molecular sieve substantially free of hydrogenation components, said catalyst having a specific gravity less than about 1.8, preferably 1.1 to 1.8, in a reaction zone at hydrocarbon hydroconversion conditions; also, said catalyst.

United States Patent 1191 1111 3,764,519 Meyer Oct. 9, 1973 [54] HYDROCARBON HYDROCQNVERSION 2,971,901 2/1961 Halik et a1. 208/59 PROCESS USING SIEVE IN 2,987,466 6/1961 Senger et a1. 208/60 3,043,769 7/1962 Nathan et al. 208/112 ALUMINA'SILICA'MAGNESIA MATRIX 3,078,238 2/ 1963 Beuther et a1. 252/439 [75] Inventor: Jarold A. Meyer, Concord, Calif. 3,079,329 2/1963 Browning 208/157 3,140,251 7/1964 Plank et al 208/120 [73] Asslgneei 'f Reseflf'ch Company, San 3,140,253 7/1964 Plank et a1 208/120 Franclsco, Cahf- 3,399,132 8/1968 Mulaskey 208/111 Filed Dec 11 1972 3,598,719 8/1971 White 208/59 [21] Appl. No.: 314,044 Primary ExaminerDelbert E. Gantz Assistant ExaminerG. E. Schmitkons U.S. Apphcauon Data Att0rr1eyJ. A. Buchanan, Jr. et a1. [63] Continuation-impart of Ser. No. 150,857, June 3,

1971, abandoned. ABSTRACT [52] U.S. Cl 208/111, 208/57, 208/58, A hydrocarbon hydroconversion pr ss mprising 208/59, 208/60, 203/61, 208/210, 203/216 contacting a hydrocarbon feedstock and hydrogen 2()8/254 H 252/455 Z 252/477 R with a catalyst comprising an alumina-silica-magnesia 51 10 13 02, 310 37 00, co 33 23 matrix containing a hydrogenation component, and a [58] Field of Search 208/59, 1 1 1 crystalline Zeolitic molecular Sieve Substantially free of hydrogenation components, said catalyst having a spe- [56] R fe e Ci d cific gravity less than about 1.8, preferably 1.1 to 1.8, UNITED STATES PATENTS in a reaction zone at hydrocarbon hydroconversion 2 769 769 11/1956 Tyson 208/60 conditions; also Said catalyst 2,956,002 10/1960 Folkins 208/59 12 Claims, 1 Drawing Figure NON "MqO CONTAINING CATALYST 1-1sv=o.e m u. 73 O I I :5 6 D U L; 720 MgO CONTAINING 11.1 CATALYST; LHSV=1.0 1 5 710 m LiJ I'- l I l I I I O 50 100 I50 200 250 300 HOURS ON-STREAM PATENTED l973 T NS 0L mL wa MS U CU NT 0 T NC 0 o 0 O O 4 3 2 1 O 7 7 7 7 7 HOURS ON-STREAM AT Tonumfs HYDROCARBON HYDROCONVERSION PROCESS USING SIEVE IN ALUMINA-SILICA-MAGNESIA MATRIX CROSS REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of U.S. application Ser. No. 150,857, filed June 3, 1971, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to processes for the hydroconversion of hydrocarbon feedstocks, specifically hydrocracking and hydrodenitrification processes, to produce high-value fuel products such as jet fuels and gasoline, and a novel catalyst for use in said processes.

The prior art, for example Plank et al., U.S. Pat. No. 3,140,253, discloses a catalyst comprising a crystalline zeolitic molecular sieve component associated with other catalyst components. Plank et al. US. Pat. No. 3,140,253, further discloses that at least some of the other catalyst components may be in the form of a matrix in which the molecular sieve component is disposed and that such catalysts may be used for catalytic cracking, hydrocracking, and hydrofining. Other prior art patents disclosing one or more of the foregoing matters include U.S. Pat. No. 3,140,251, British Pat. 1,056,301, French Pat. 1,503,063, and French Patent 1,506,793. The prior art further shows use of silicaalumina-magnesia catalysts for cracking, hydrocracking, and hydrofining. The prior art does not, however, show the unique advantages obtainable, namely improved activity and stability, in hydrocarbon hydroconversion processes which comprise contacting a hydrocarbon feedstock and hydrogen with a catalyst comprising an alumina-silicia-magnesia matrix containing a hydrogenation component and a crystalline zeolitic molecular sieve substantially free of hydrogenation components in a reaction zone at hydrocarbon hydroconversion conditions, the catalyst having a specific gravity less than about 1.8, preferably 1.1 to 1.8.

SUMMARY OF THE INVENTION The invention is concerned with a hydrocarbon hydroconversion process comprising contacting a hydrocarbon feedstock and hydrogen with a catalyst comprising an alumina-silica-magnesia matrix containing a hydrogenation component and a zeolitic molecular sieve substantially free of hydrogenation components (unloaded) dispersed in the alumina-silicia-magnesia matrix, in a reaction zone at hydrocarbon hydroconversion conditions, said catalyst having a specific gravity of less than 1.8, preferably about 1.1 to 1.8, and more preferably 1.2 to 1.7; and with the novel catalyst used in said hydrocarbon hydroconversion process.

Examples of hydrocarbon conversion processes in which the catalyst of the invention is useful include hydrocracking, isomerizing, reforming, and hydrofining, particularly hydrode-nitrification, processes. Preferably, the catalyst is used in hydrocracking and hydrofining processes or combined single-stage hydrofininghydrocracking processes.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE illustrates starting and average run temperatures of single-stage combined hydrofining and hydrocracking processes using a comparison catalyst of the prior art and the catalyst of the present invention at pressures of approximately 2,000 psig.

DETAILED DESCRIPTION OF THE INVENTION This invention comprises a novel catalyst composition of matter and hydrocarbon conversion processes using this novel catalyst.

The catalyst of this invention consists of two compo nents, as follows:

1. a matrix containing silica, alumina and magnesia and having associated with it at least one hydrogenation component; and

2. A crystalline zeolitic molecular sieve which is substantially free of any hydrogenation components. The final catalyst is a mixture of the matrix component, the hydrogenation component and the crystalline zeolite component, such that the zeolite component is intimately dispersed throughout the matrix component.

The matrix component must contain silica, alumina and magnesia. Suitable compositions are within the following ranges, based upon the silica-alumina-magnesia content:

Component Minimum Wt. Maximum Wt. Silica 2 96 Alumina 2 96 Magnesia 2 50 Preferred compositions, especially for hydrodenitrification and hydrocracking catalysts, are within the following ranges, based upon the silica-aluminamagnesia content:

Component Minimum Wt. Maximum Wt. Silicia 20 Alumina 20 60 Magnesia 5 30 The matrix component also contains at least one hydrogenation component. Examples of useful hydrogenation components are metals of Group Vl-B and Group VIII of the Periodic Table. Preferably the hydrogenation component is selected from the group consisting of nickel, cobalt, molybdenum, tungsten, palladium, platinum, compounds of these components, or combinations thereof.

The matrix component may also include other components. The matrix preferably also includes a Group lV-B component, i.e., titanium, zirconia, hafnia, or compounds thereof. The term matrix as used herein in defining weight percents of the various components refers to the silica-alumina-magnesia component of the catalyst. As discussed herein, a hydrogenation component is also present in the matrix.

If no noble metal hydrogenation componet is used, the preferred amounts of the components fall within the following ranges, based upon the final catalyst composition:

Component Minimum Wt. Maximum Wt. Silicia-i-alumina+magnesia 2O Group lV-B O 20 Group Vl-B 3 35 Group VIII 3 20 Zeolite 2 50 lyst composition:

Component Minimum Wtv %Maximum Wt. Silicia+alumina+magnesia 27 97, preferably 95 Group lV-B 0, preferably 2 20 Group VIII 0.05 3.0 Zeolite 2 50 In the above, the Group IV-B components are calculated as the oxides and the Group VIII noble metal components as the metal.

Compositions with catalytic activity containing both noble metal and nonnoble metal hydrogenation components also form part of this invention. These compositions are similar to those described above for nonnoble metal catalysts, but contain 0.053.0 weight percent of the noble metal component, based on the final catalyst and calculated as the metal.

In the above compositions, the preferred crystalline zeolitic molecular sieve is Y-type zeolite. In the final catalyst, a substantial portion of the crystalline zeolitic material preferably is in the hydrogen form, and is substantially free of hydrogenation components.

The matrix component and zeolite component of the final catalyst may be combined in many ways. Examples include separate preparation of dried materials followed by cotabletting, addition of the zeolite component to a washed gel of the matrix component followed by extrusion or tabletting, etc. It is preferred that the catalyst be formulated by a cogelation technique. For example, an acidic solution containing silica; alumina; magnesia; a Group IV-B component, if present; a hydrogenation component; and preferably a detergent, alcohol, polymer, or other organic compound, may be formulated at a pH below 5. Ammonium hydroxide may then be added until the pH reaches about 5. The crystalline zeolitic molecular sieve is added at a pH of about 5. Other components, for example tungsten, if tungsten is to be present in the final catalyst, may also be added at a pH of about 5. The pH can then be increased to 7 by addition, for example, of ammonium hydroxide. If the catalyst is made in this preferred manner, the crystalline zeolitic molecular sieve will be substantially unloaded, i.e., free of any hydrogenation components. The now-neutral solution containing the catalyst may be filtered to recover the catalyst, which may then be washed with, for example, ammonium acetate and dried, for example, at 150F. to 400F. and then calcined at a temperature in the range from about 700F. to about 1,300F.

It is essential to the practice of the invention that the catalyst have a specific gravity less than about 1.8, preferably in the range from about 1.1 to about 1.8, more preferably from about 1.2 to about 1.7. If a catalyst comprising an alumina-silicia-magnesia matrix and a zeolitic molecular sieve component is formulated by, for example, cogelation, it will generally have a specific gravity above about 1.9. The catalyst can, however, be prepared with a lower specific gravity by many methods, for example by incorporating a detergent, an alcoho], a polymer, or another organic compound with the components during the formation of the gel, by drying the catalyst in an atmosphere that has a relatively high content of water, by hot-aging the catalyst, i.e., allowing the gel to age in solution before filtering (generally a slurry of 3-5 weight percent solids suspended in H O), for example at a temperature of F. to about 250F. for from about 1 to about 8 hours, preferably at a water partial pressure above about 15 psia and at elevated temperature, e.g., 215F. to 250F., by grinding a catalyst having an undesirably high specific gravity and forming it into tablets, by combinations of the above methods, or by other methods as well. Preferably a detergent, an alcohol, a polymer, or another organic compound is incorporated with the catalyst components during the formation of the gel.

FEEDSTOCKS The hydrocarbon feedstocks that are processed by the method of this invention, preferably in a hydrofining, hydrocracking, or combined (single-stage) hydrofining and hydrocracking operation, preferably boil above about 400F. and more preferably boil within the range from about 550F. to about 1,000F. The nitrogen content of the feedstocks may be within the range from about 10l0,000 ppm. After hydrofining or combined hydrofining and hydrocracking, the nitrogen content of the feedstocks is preferably reduced to below about 50 ppm. Similary, the sulfur content of the feedstocks is generally reduced during hydrofining and- /or hydrocracking operation.

PROCESS CONDITIONS Typical hydrofining, hydrocracking and combined single-stage hydrofining and hydrocracking conditions include, for example, temperatures from about 500F. to about 900F., hydrogen pressures from about 200 psig to about 3000 psig, hydrogen flow rates from about 2,000 standard cubic feet per barrel of feed to about 20,000 SCF per barrel of feed, and liquid hourly space velocities (LHSV) from about 0.3 to about 5.0.

A preferred embodiment of the present invention comprises a combined (single-stage) hydrofining and hydrocracking process comprising contacting a nitrogen-containing hydrocarbon feedstock with hydrogen and a catalyst of the invention.

Another preferred embodiment of the invention is a hydrocracking process comprising contacting a hydrocarbon feedstock boiling above about 550F. with hydrogen and a catalyst comprising an alumina-silicamagnesia matrix containing a Group IV-B component selected from the group consisting of titania, zirconia, and hafnia, a Group VI component selected from the group consisting of tungsten and molybdenum, and a Group VIII component selected from the group consisting of platinum, palladium, nickel and cobalt, and an unloaded crystalline zeolitic molecular sieve component, the catalyst having a specific gravity in the range from about 1.2 to about 1.7, in a hydrocracking zone at hydrocracking conditions, Preferably the crystalline zeolitic molecular sieve is a Y-type zeolite.

The invention will be better understood by reference to the illustrative examples which follow.

EXAMPLES EXAMPLE 1 A catalyst of the prior art, Catalyst A, comprising 10 parts by weight of nickel oxide, 25 parts tungsten trioxide, 27 parts silicon dioxide, 30 parts alumina, 8 parts titanium dioxide, and parts of a Y-zeolite in hydrogen form, said zeolite being free of catalytic metals, was formed by cogelation. Catalyst A was formed by combining nickel chloride, silica, aluminum chloride, and titanium tetrachloride in a water-hydrogen-chloride solution at a pH below 5. The pH was then adjusted to 5 with ammonium hydroxide and the zeolite and ammonium paratungstate were added. Then the pH was adjusted to 7 with more ammonium hydroxide. The resulting precipitate was filtered, washed with 1 percent ammonium acetate, dried at 400F., and then calcined at 950F. The particle density of Catalyst A was approximately 1.6 grams per cubic centimeter.

A catalyst of this invention, Catalyst B, was prepared exactly as Catalyst A was prepared except that magnesium chloride was added along with the nickel chloride, silica, aluminum chloride and titanium tetrachloride. Also, the final wash contained 0.1 percent by weight of a nonionic detergent to lower the catalyst particle density. Catalyst B comprised 1 1.4 parts nickel oxide, 25.5 parts tungsten trioxide, 22.4 parts silicon dioxide, 22.4 parts alumina, 10.4 parts magnesium oxide, 7.9 parts titania, and 10 parts hydrogen-form Y-type zeolite, all of the above parts being by weight. The density of Catalyst B was approximately 1.67 grams per cubic centimeter.

A feedstock with the following properties was hydrofined and hydrocracked in a single-stage operation using Catalyst A, at a total pressure above 2,000 psig and with that portion of the product boiling above 550F. being recycled.

Feedstock Analysis Volume Distillation "F. Paraffins 7.1 Start 477 Naphthenes 78.2 5% 584 Aromatics 14.7 10% 610 30% 665 50% 720 70% 761 90% 816 95% 841 End Point 888 The feedstock contained approximately 0.74 percent sulfur and approximately 2,800 ppm nitrogen.

The run conditions were:

Starting and Average Catalyst Temperature 730F. Liquid Hourly Space Velocity 0.8 Per-Puss Conversion 49.5% Total Pressure 2012 psig The product obtained had the following characteris- The 300F.-550F. product had the following inspection:

API Gravity 41.4 Smoke Point 25 mm Freeze Point Below 94F. Paraffin Content 17.3% Nuphthene Content 73.6% Aromatic Content 9.1%

The ASTM D-86 distillation of the product showed a 10 percent point of 349F., a 50 percent point of 398F., and a 90 percent point of 470F.

Catalyst B was used to hydrofine and hydrocrack, in a single-step operation at 2,000 psig and with that portion of the product boiling above 550F. being recycled, a feed having the following properties:

Analysis of Feed Volume Distillation F. Paraffins 6.1 Start 450 Naphthenes 78.2 5% 546 Aromatics 15.7 10% 590 30% 653 50% 703 761 820 837 End Point 888 The feedstock had approximately 0.81 percent sulfur and approximately 2,600 ppm nitrogen. This feedstock is essentially identical with the feedstock used to test Catalyst A.

The run conditions were as follows:

Starting and Average The 300F.-550F. product had the following inspection:

API Gravity 39.5 Smoke Point 21 mm Freeze Point Below 94F. Paraffias 16.7 Wt. Naphthenes 71.6 Wt. Aromatics 11.7 Wt.

ASTM D-86 distillation 10 percent point, 356F; 50% point, 418F., 90percent point, 500F.

From these data it can be seen that the products produced using Catalysts A and B were comparable.

Further, the catalyst containing magnesia, Catalyst B, was superior to the catalyst without magnesia, Catalyst A, in starting temperature. The actual starting temperature was 723F. for the catalyst containing magnesia and 730F. for the catalyst without magnesia, yet the catalyst containing magnesia was used at a liquid hourly space velocity of 1.0 whereas the catalyst without magnesia was used at a liquid hourly space velocity of 0.8. If the liquid hourly space velocity had been 1.0 in each case, the difference in starting temperature would not have been 7F., but would instead have been about 14F. FIG. 1 illustrates that the starting temperature differential is maintained after considerable time on-stream.

Thus, Catalyst B, the catalyst of the invention, is superior to Catalyst A in that it is substantially 14F. more active at 2,000 psig and at a space velocity of 1.0.

EXAMPLE 2 Catalyst C was prepared with a composition very similar to Catalyst B of Example 1, by the same procedure as Catalyst B except that no processing step was included to lower the catalyst particle density. Catalyst C comprised 10.2 parts by weight nickel oxide, 22.8 parts tungsten oxide, 30 parts silicon dioxide, 15 parts alumina, l5 parts magnesium oxide, 7 parts titania, and 10 parts hydrogen form of Y zeolite. The particle density of Catalyst C was 1.99 grams per cubic meter. Catalyst C particle density is nearly 20 percent greater than the particle density of Catalyst B.

Catalyst C was compared to Catalyst A of Example 1 for hydrocracking the same test feed used for Catalyst A in Example l.ln these tests the liquid flow was once-through; i.e., the unconverted feed was not recycled back through the reactor. Test conditions and results were as follows:

Catalyst A A C C Run length, hours 20 250 20 250 LHSV, l/hr. 1.0 1.0 1.0 1.0 Total pressure, psig 1,300 1,300 L300 1,300 Hydrogen, SCF/B. 10,000 10,000 10,000 10,00 Catalyst temperature, F. 768 785 764 790 Conversion to 550F. products, LV% of feed 63 63 59 59 Temperature for 63% conversion 768 785 Estimated temperature for 63% conversion 770 796 Temperature change needed for constant conversion, F./hr. 0.07 0.1 l

lt can be seen that the temperature required for 63 percent conversion was 2F. higher for Catalyst C than for Catalyst A after 20 hours operation. In addition, the temperature increase per hour required to maintain constant conversion was higher for Catalyst C than Catalyst A. Thus, after 250 hours operation, the temperature required for 63 percent conversion for Catalyst C was 1 lF. higher than for Catalyst A.

It is clear from these results that high-density Catalyst C is inferior in both catalytic activity and stability to Catalyst A. However, lower-density Catalyst B (of similar composition to Catalyst C) was shown to be superior to Catalyst A in Example 1. Thus, to achieve superior performance with the magnesia-containing catalysts, it is necessary that the particle density be less than about 1.8 g./cc. It is apparent that many widely different embodiments of this invention may be made without departing from the scope and spirit thereof; and, therefore, it is not intended to be limited except as indicated in the appended claims.

What is claimed is:

1 l. A hydrocarbon hydroconversion process comprising: contacting a hydrocarbon feedstock and hydrogen with a catalyst comprising an alumina-silica-magnesia matrix, a hydrogenation component, and a crystalline zeolitic molecular sieve substantially free of hydrogenation components dispersed in the alumina-silicamagnesia matrix, in a reaction zone at hydrocarbon hydroconversion conditions, said catalyst having a specific gravity of less than about 1.8.

2. A process as in claim 1 wherein said catalyst has a specific gravity in the range of from about 1.1 to about 1.8.

3. A process as in claim 2 wherein the matrix also comrises a Group lV-B component selected from the group consisting of titania, zirconia, and hafnia.

4. A process as in claim 2 wherein the hydrogenation component is selected from the group consisting of a Group Vl component and a Group VIII component.

5. A process as in claim 2 wherein the hydrogenation component is selected from the group consisting of tungsten, molybdenum, platinum, palladium, nickel and cobalt.

6. A hydrocracking process, comprising:

contacting a hydrocarbon feedstock boiling above about 400F. with hydrogen and a catalyst comprising: (1) an alumina-silica-magnesia matrix associated with a Group IV-B component selected from the group consisting of titania, zirconia, and hafnia, a Group VI component selected from the group consisting of tungsten and molybdenum, and a Group VIII nonnoble metal component selected from the group consisting of nickel and cobalt; and (2) a crystalline zeolitic molecular sieve substantially free of hydrogenation components dispersed in the alumina-silica-magnesia matrix, said catalyst having a specific gravity in the range from about 1.1 to about 1.8, in a hydrocracking zone at hydrocracking conditions.

7. A process as in claim 6 wherein the crystalline zeolitic molecular sieve is a Y-type zeolite in the ammonium or hydrogen form.

8. A process as in claim 6 wherein the alumina is present in an amount of from 2-96 weight percent, the silica is present in an amount of from 2-96 weight percent, the magnesia is present in amount of from 2-50 weight percent, the respective weight percents of alumina, silica and magnesia based on said matrix; said matrix being present in the final catalyst in an amount of from 20 to percent by weight, based on the final catalyst; the Group IV-B component is present in an amount of from 2-20 weight percent, calculated as the oxide, based on the final catalyst; the Group Vl component is present in an amount of from 3-35 weight percent, calculated as the oxide, based on the final catalyst; the Group VIII nonnoble metal component is present in an amount of from 3-20 weight percent, calculated as the oxide, based on the final catalyst; and said molecular sieve is present in an amount of from 2 to 50 percent by weight, based on the final catalyst.

9. A hydrocracking process, comprising:

contacting a hydrocarbon feedstock boiling above about 400F. with hydrogen and a catalyst comprising; (1) an alumina-silica-magnesia matrix associated with a Group lV-B component selected from the group consisting of titania, zirconia, and hafnia,

and a Group VIII noble metal component selected from the group consisting of platinum and palladium; and (2) a crystalline zeolitic molecular sieve substantially free of hydrogenation components, dispersed in the alumina-silica-magnesia matrix, said catalyst having a specific gravity in the range from about 1.1 to about 1.8, in a hydrocracking zone at hydrocracking conditions.

10. A process as in claim 9 wherein the alumina is present in an amount of from 2-96 weight percent, the silica is present in an amount of from 2-96 weight percent, the magnesia is present in an amount of from 2-50 weight percent, the respective weight percents of alumina, silica and magnesia based on said matrix, said matrix being present in the final catalyst in an amount of from 27 to by weight, based on the final catalyst; the Group IV-B component is present in an stock boiling above about 400F. with hydrogen and a catalyst comprising a matrix including alumina, silica, and magnesia, and titania or zirconia; a crystalline zeolitic molecular sieve substantially free of hydrogenation components dispersed in particulate form in said matrix; tungsten or molybdenum; and platinum, palladium, nickel or cobalt; said catalyst having a specific gravity within the range from about 1.2 to about 1.7, in a hydrofininghydrocracking zone at hydrofining-hydrocracking conditions. 

2. A process as in claim 1 wherein said catalyst has a specific gravity in the range of from about 1.1 to about 1.8.
 3. A process as in claim 2 wherein the matrix also comrises a Group IV-B component selected from the group consisting of titania, zirconia, and hafnia.
 4. A process as in claim 2 wherein the hydrogenation component is selected from the group consisting of a Group VI component and a Group VIII component.
 5. A process as in claim 2 wherein the hydrogenation component is selected from the group consisting of tungsten, molybdenum, platinum, palladium, nickel and cobalt.
 6. A hydrocracking process, comprising: contacting a hydrocarbon feedstock boiling above about 400*F. with hydrogen and a catalyst comprising: (1) an alumina-silica-magnesia matrix associated with a Group IV-B component selected from the group consisting of titania, zirconia, and hafnia, a Group VI component selected from the group consisting of tungsten and molybdenum, and a Group VIII nonnoble metal component selected from the group consisting of nickel and cobalt; and (2) a crystalline zeolitic molecular sieve substantially free of hydrogenation components dispersed in the alumina-silica-magnesia matrix, said catalyst having a specific gravity in the range from about 1.1 to about 1.8, in a hydrocracking zone at hydrocracking conditions.
 7. A process as in claim 6 wherein the crystalline zeolitic molecular sieve is a Y-type zeolite in the ammonium or hydrogen form.
 8. A process as in claim 6 wherein the alumina is present in an amount of from 2-96 weight percent, the silica is present in an amount of from 2-96 weight percent, the magnesia is present in amount of from 2-50 weight percent, the respective weight percents of alumina, silica and magnesia based on said matrix; said matrix being present in the final catalyst in an amount of from 20 to 90 percent by weight, based on the final catalyst; the Group IV-B component is present in an amount of from 2-20 weight percent, calculated as the oxide, based on the final catalyst; the Group VI component is present in an amount of from 3-35 weight percent, calculated as the oxide, based on the final catalyst; the Group VIII nonnoble metal component is present in an amount of from 3-20 weight percent, calculated as the oxide, based on the final catalyst; and said molecular sieve is present in an amount of from 2 to 50 percent by weight, based on the final catalyst.
 9. A hydrocracking process, comprising: contacting a hydrocarbon feedstock boiling above about 400*F. with hydrogen and a catalyst comprising; (1) an alumina-silica-magnesia matrix associated with a Group IV-B component selected from the group consisting of titania, zirconia, and hafnia, and a Group VIII noble metal component selected from the group consisting of platinum and palladium; and (2) a crystalline zeolitic molecular sieve substantially free of hydrogenation components, dispersed in the alumina-silica-magnesia matrix, said catalyst having a specific gravity in the range from about 1.1 to about 1.8, in a hydrocracking zone at hydrocracking conditions.
 10. A process as in claim 9 wherein the alumina is present in an amount of from 2-96 weight percent, the silica is present in an amount of from 2-96 weight percent, the magnesia is present in an amount of from 2-50 weight percent, the respective weight percents of alumina, silica and magnesia based on said matrix, said matrix being present in the final catalyst in an amount of from 27 to 95% by weight, based on the final catalyst; the Group IV-B component is present in an amount of from 2-20 weight percent, calculated as the oxide, based on the final catalyst; the Group VIII noble metal component is present in an amount of from 0.05-3.0 weight percent, calculated as the metal, based on the final catalyst; and said molecular sieve is present in an amount of from 2-50 percent by weight, based on the final catalyst.
 11. A process in accordance with claim 8 wherein the crystalline zeolitic molecular sieve is a Y-type zeolite in the ammonium or hydrogen form.
 12. A combined single-stage hydrofining and hydrocracking process, comprising: contacting a nitrogen-containing hydrocarbon feedstock boiling above about 400*F. with hydrogen and a catalyst comprising a matrix including alumina, silica, and magnesia, and titania or zirconia; a crystalline zeolitic molecular sieve substantially free of hydrogenation components dispersed in particulate form in said matrix; tungsten or molybdenum; and platinum, palladium, nickel or cobalt; said catalyst having a specific gravity within the range from about 1.2 to about 1.7, in a hydrofining-hydrocracking zone at hydrofining-hydrocracking conditions. 